The invention relates to a heater using PTC (positive temperature coefficient) thermal ceramic resistor as the heating element.
PTC heater is developed rapidly in recent years. It has been applied in electric products such as air heater, drier, water heater, air conditioner and so on. The characteristics of it are automatic heat adjustment, rapid heating-up and small electrical pressure undulations. Traditional PTC heater assemblies are made of aluminium corrugation cooling fins stuck together by silica gel. The surface of the aluminium fins is usually electrified, so the aging of the silica gel and the lowering of its bonding ability would lead to instability and attenuation of the heating power of the heater assembly. Especially the heater has many hidden dangers in electric performance. The surface of cooling fins is electrified. In case of the drop off of the aluminium chips or other conductive medium, short or even a fire will happen. Because of the influence of creepage clearance, traditional products have a lot of restrictions in installation and use, in addition, they can not be operated in safety, spark and short often happen.
The object of the invention is to provide a PTC heater, which could keep the stability of power for a long time and its surface is not electrified.
To achieve above object, according to the invention, a PTC heater is provided, which mainly comprises PTC ceramic sheets and cooling fins, and is characterized by comprising an inner support in which the PTC sheets are disposed, two electrode plates being disposed on both sides of the support and the PTC sheets to abut against the PTC sheets tightly, the cooling fins being disposed at the exterior of the electrode plates, insulating plates being mounted between the cooling fins and the electrode plate, in the interior of upper and lower ends of the two cooling fins, corresponding clamping grooves being formed through which the two cooling fins are clamped together, and elastic rods being inserted in the clamping grooves.
Mechanical clamping method is adopted in this invention. The fitting structure of the elastic rod and the clamping grooves of cooling fins has taken the place of the traditional gluing structure, so the problem of aging of the silica gel and the lowering of power in traditional products is solved thoroughly. The PTC heater according to the invention is prevented from sparking and shorting and has a good safety and cooling performance. The surface of the heater is not electrified so that the heater has more safety. The heater has an original structure and good shape.